CN104882778B - The method and apparatus for jumping the noise of generation for reducing mode in outside cavity gas laser - Google Patents
The method and apparatus for jumping the noise of generation for reducing mode in outside cavity gas laser Download PDFInfo
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- CN104882778B CN104882778B CN201510080016.2A CN201510080016A CN104882778B CN 104882778 B CN104882778 B CN 104882778B CN 201510080016 A CN201510080016 A CN 201510080016A CN 104882778 B CN104882778 B CN 104882778B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/14—External cavity lasers
- H01S5/141—External cavity lasers using a wavelength selective device, e.g. a grating or etalon
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/08—Construction or shape of optical resonators or components thereof
- H01S3/08004—Construction or shape of optical resonators or components thereof incorporating a dispersive element, e.g. a prism for wavelength selection
- H01S3/08009—Construction or shape of optical resonators or components thereof incorporating a dispersive element, e.g. a prism for wavelength selection using a diffraction grating
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/065—Mode locking; Mode suppression; Mode selection ; Self pulsating
- H01S5/0651—Mode control
- H01S5/0652—Coherence lowering or collapse, e.g. multimode emission by additional input or modulation
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
- H01S5/0683—Stabilisation of laser output parameters by monitoring the optical output parameters
- H01S5/0687—Stabilising the frequency of the laser
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/105—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the mutual position or the reflecting properties of the reflectors of the cavity, e.g. by controlling the cavity length
- H01S3/1055—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the mutual position or the reflecting properties of the reflectors of the cavity, e.g. by controlling the cavity length one of the reflectors being constituted by a diffraction grating
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/13—Stabilisation of laser output parameters, e.g. frequency or amplitude
- H01S3/139—Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling the mutual position or the reflecting properties of the reflectors of the cavity, e.g. by controlling the cavity length
- H01S3/1398—Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling the mutual position or the reflecting properties of the reflectors of the cavity, e.g. by controlling the cavity length by using a supplementary modulation of the output
Abstract
A kind of method and apparatus jumping the noise of generation for reducing mode in outside cavity gas laser.Disclose a kind of outside cavity gas laser and the method for operating the outside cavity gas laser.The outside cavity gas laser includes chip gain, grating, actuator and actuator drive.The optical diffraction that the chip gain is left in wavelength band is returned to the chip gain by the grating, the grating is characterized by the angle relative to the light for leaving the chip gain and the distance away from the chip gain, and the angle and the distance are controlled by the actuator.Light after a part of diffraction is amplified by the chip gain.The driver driver makes the angle in the movement by amplitude and average frequency characterization relative to balance angle jitter.The jitter motion amplitude is chosen, to motivate multiple adjacent laser modes of the chip gain or provide the servosignal for grating angle to be maintained to target value.
Description
Technical field
This disclosure relates to the method and apparatus for jumping the noise of generation for reducing mode in outside cavity gas laser.
Background technique
It, can be throughout wide wave-length coverage using having in big metering device of the measurement as the property of the sample of function of wavelength
The laser of the output wavelength tuned.A kind of laser utilized in these devices is based on broadband wide-gain chip, puts
It sets in using exocoel of the grating as one of each " reflector " in exocoel.For tuning operation wavelength, the position of grating by
Adjustment, the incident angle of the light to provide desired laser cavity length, and on grating are adjusted, so that grating selectively will
It is expected that the optical diffraction of wavelength returns to chip gain.
If the wavelength band that grating is diffracted back is sufficiently large, more than one laser cavity modes may be motivated.Herein
In the case of, period smaller period that laser output light may be used to measure from the device of the light of laser in Billy
On jumped between each mode with uncertain pattern.Any possibility in a large amount of non-ideal factors (such as change of temperature)
Cause to jump.In pulsed laser device, when current impulse is applied to chip gain, insufficient grating resolution allows to be more than
One laser cavity modes meets Laser emission condition.Although other physical mechanisms (such as uniform gain broadening) only permit one
Laser cavity modes emit laser, but Laser emission cavity mold formula can be different with pulse.In pulsed laser device, pulse period
Between the variation of temperature there may be modes to jump (pulse internal schema jumps).It is associated additionally, there are being jumped with zlasing mode
Laser beam error in pointing.Because each laser cavity has different frequencies, the angle of the light after grating diffration
Each laser cavity modes are different.
Repeatedly tuned laser wavelength and good laser beam are directed toward a large amount of measurement requests during each measurement
Stability.For example, when sample missing background can be removed from sample signal by measurement background.In these measurements, swash
Light device wavelength tuning repeatability is very important.It may be generated in random time since mode jumps, these variations
For requiring the survey of high tuning repeatability degree and good laser beam pointing stability in the tuning of laser wavelength
Amount is led to the problem of.
Summary of the invention
The present invention includes a kind of outside cavity gas laser and the method for operating the outside cavity gas laser.The external cavity laser
Device includes chip gain, grating, actuator and actuator drive.The grating will leave the chip gain in wavelength band
Optical diffraction returns to the chip gain, the alignment of the grating by relative to the light for leaving the chip gain angle and away from
The distance of the chip gain characterizes, and the angle and the distance are controlled by the actuator.After a part of diffraction
Light is amplified by the chip gain.The actuator drive makes the angle in the movement by amplitude and average frequency characterization
In relative to balance angle jitter.The amplitude is enough to motivate more than first a adjacent laser modes of the chip gain.
In one aspect of the invention, the actuator drive makes the angle by the average frequency greater than 1Hz
Shake.In another aspect of the invention, the actuator drive presses the resonance as the mechanical system for including the grating
The frequency of frequency makes the angle jitter.
In another aspect of the invention, the chip gain presses first frequency chopping, and the grating angle is by being less than
The frequency jitter of the first frequency.
In still yet another aspect of the present, the outside cavity gas laser includes: detector, measures laser power and servo
The actuator drive, so that the peak value of the grating diffration function is aligned with desired laser cavity modes.
In one aspect of the invention, the long-focus lens with bigger numerical aperture is for collimating on the grating
Light beam, to improve the selectivity of the grating.
Detailed description of the invention
Fig. 1 shows the outside cavity gas laser according to an embodiment of the invention for providing the light to measuring system.
Fig. 2 shows the possibility laser cavity modes of the function as laser optics frequency.
Fig. 3 shows the selection of optical frequency provided by diffraction grating.
Fig. 4 shows the ideal relationship between the mode of laser and grating diffration function.
Fig. 5 shows the mode and diffraction function of the grating when being improperly directed at grating.
Specific embodiment
The present invention can be more easily to understand referring to Fig.1, the mode of its advantage is provided, Fig. 1 shows a reality according to the present invention
Apply the outside cavity gas laser for providing the light to measuring system 41 of example.Laser 10 includes the chip gain mounted in attachment portion 12
11.Laser cavity is limited by the section 14 of chip gain 11 and grating surface.In idealized system, choose diffraction grating 16 relative to
The angle of light beam from chip gain 11, by laser lock-on on AD HOC.The angle is arranged by actuator 15, causes
Move device 15 around 23 rotating grating of axis, be chosen for so that back to chip gain 11 diffraction after light wavelength and laser
The length of chamber is maintained, to provide desired output wavelength.Lens 17 collimate output light for desired beam size, to mention
For to the light by being used using laser 10 as the measuring system of its light source.The collimation of collimation lens 22 leaves chip gain 11
The light of preceding section 13, to provide the collimated light with the diameter for being set as providing desired wavelength resolution from diffraction grating 16
Beam.Increase the quantity of the groove on the diffraction grating 16 that laser beam is covered in the light after the diffraction for reaching chip gain 11
Narrower wavelength band is provided.In order to reduce the bandwidth for the light for returning to chip gain by grating, long focus lens (have big numerical aperture
Diameter) it can be used for increasing the size of laser beam on grating surface.In laser 10, optional light output 21 is also given birth to
At, and it is used for 19 laser power monitoring of detector.It is will be discussed in more detail below in the laser for stablizing excited target
The use of detector 19 in mode.Alternatively, the light beam divider in beamformer output can be used for deflecting a small amount of laser power
To photodetector.
Referring now to Fig. 2, Fig. 2 shows the possibility laser cavity modes of the function as laser optics frequency.Generally usefully,
The wavelength for using light of the discussed laser optics frequency rather than from laser, this is because laser cavity modes are as optics
The function of frequency and be equably separated by.Any wavelength band in laser is equivalent to corresponding optical frequency band.Two adjacent lasers
Difference on the frequency between cavity mold formula is known as free spectral range (FSR).The bandwidth of chip gain 11 is very big compared with the FSR of laser cavity；
Therefore, it is necessary to certain Additional optical frequency selective elements, to ensure only one of each laser cavity modes transmitting laser.These optics frequency
The example of rate selection element includes diffraction grating and dispersing prism.
Diffraction grating 16 shown in FIG. 1 provides the selection of Additional optical frequency.16 institute of diffraction grating is shown referring now to Fig. 3, Fig. 3
The optical frequency of offer selects.Wave beam after being shown as the diffraction back to chip gain of the function of optical frequency at 51
In light amplitude.In the following discussion, which is referred to as grating diffration function, or referred to as diffraction function.Diffraction letter
Number is that the wavelength of maximum value is referred to as diffraction function maximum value.Although grating preferentially makes and f0Different frequency decays, but spread out
The amplitude of light after penetrating is away from f0It is still significant at the frequency of displacement.Ideally it is desirable to zlasing mode be in f0Place, as frequency
The amplitude of light after the diffraction of the function of rate is as shown in Figure 4.In the case, the amplitude of the light after the diffraction at mode 52 and 53
It fully reduces, to ensure that only mode 54 emits laser.
In fact, diffraction function maximum frequency f0Misalignment between laser cavity modes occurs.Fig. 5 shows this misalignment.
In the case, mode 55 and 56 can emit laser；Although only one mode will emit laser at any given time.This
Outside, the mode of just transmitting laser may jump back and forth between these two modes.In pulse laser, when current impulse is injected
When into chip gain, laser can emit laser in one of mode 55 and 56.Diffraction frequency f0With laser cavity modes
Misalignment may cause laser orientation unstability.For given stop position, only one optical frequency f0Excellentlyly and laser
Chamber alignment.Light beam with different optical frequencies is when it is returned from grating with different angle of diffraction.Accordingly, it is possible to motivate
Mode with different transmission directions.This is that laser beam is directed toward instable one of rise.In some cases, in gain
There are waveguides in chip 11.The basic mode (fundamental mode) of waveguide limits the laser beam transmission direction of desired pattern.
In this configuration, other than the basic mode of the waveguide of chip gain 11, have and return to laser gain chip with optical grating diffraction
F0The light beam of different frequencies motivates higher order transverse mode (transverse mode).In fact, higher order waveguide mode can not
Inhibited completely by waveguide, this leads to the direction unstability for exporting laser beam.
Referring again to Fig. 1, chip gain 11 has wide gain bandwidth, to support to swash across a large amount of of relatively large wave-length coverage
Optical cavity mode.Chip gain 11 is driven the driving of device 42, and driver 42 can be source of current pulses.Before chip gain 11
The light of section 13 is from diffraction grating 16 by diffraction.Angle of the diffraction grating 16 relative to the light beam from chip gain 11 is chosen,
Emit laser to select specific laser cavity modes.The angle is arranged by actuator 15, and actuator 15 rotates light around axis 23
Grid, be chosen for so that back to chip gain 11 diffraction after the wavelength of light and the length of chamber be maintained, to provide the phase
The laser wavelength of prestige.Lens 17 collimate beamformer output for desired beam size, to provide to by being made using laser 10
The output light used for the measuring system of its light source.Lens 22 are set the light for leaving the preceding section 13 of chip gain 11 collimation
It sets to provide the diameter of desired wavelength from diffraction grating 16.Increase the number for the groove that laser beam is covered on diffraction grating 16
It measures and provides narrower wavelength band in the light after the diffraction for reaching chip gain 11.One kind is for realizing this desired narrow wavelength
The method of band is using for the long-focus lens with larger-diameter lens 22, to provide biggish collimated wave beam.It is typical
Ground, the laser optical occurred from preceding section 13 are sent out with being not enough to fill the angle for the big lens that preceding section 13 is nearby placed
It dissipates.Therefore, it is used to increase beam diameter further away from the long-focus lens that preceding section 13 is placed, therefore increases laser beam
The quantity of the groove on grating covered.
The present invention is based on such observations: repeatable laser output is than having most narrow possible output for extensive application
Wavelength spectrum is even more important.In such systems, generate include from some desired " idealized model " between two parties it is multiple
The light source of the spectrum of the stabilization mixed light of the light of neighboring modes is preferably to have to cross over the wave between each mode discussed in joint
The source of the spectrum unpredictably jumped in the relatively narrow spectrum of long range.
In one aspect of the invention, actuator 15 is driven the driving of device 31, and driver 31 generates the driving letter of shake
Number, diffraction grating 16 is moved back and forth during the time of 10 output light of laser relative to equilbrium position.Preferably select
Equilbrium position is taken, so that the central wavelength of the light after the diffraction of arrival chip gain 11 is the wavelength of desired laser cavity modes.
In the aspect of the invention illustrated, several laser cavity modes have " equalization " chance for being used to emit laser average in time,
And pass through measurement being averaged based on these modes that device is carried out using laser 10.In the case, shake should be enough
Fastly, so that on the residence time of given measurement, there are enough equalizations to provide repeatable measurement.
Shake can be periodic or random or pseudorandom.In the feelings as exemplary periodic jitter
Under condition, chattering frequency should be equal to or more than the inverse of the residence time of the measurement using the light from laser 10.In the present invention
One aspect in, chattering frequency is the integral multiple reciprocal using the residence time of the measurement of the light from laser 10.It must
The measuring system for the output that chattering frequency does not interfere signal using laser 10 must be chosen.For example, the frequency should not be located
Near any characteristic frequency using the measuring system of the light from laser 10.It is in addition, driving signal should not have
Any harmonic wave near the characteristic frequency discussed.If laser 10 operates under pulsed mode, chattering frequency is also answered
Less than pulse frequency or pulse repetition rate.For many actual conditions, the chattering frequency between 10Hz and 2MHz is preferred.
Lower frequency requires longer time of measuring.Upper frequency is preferred；However, in the presence of as realizing machine used in actuator
Limitation set by tool system.
For periodic jitter, shakes waveform and be not limited to sinusoidal waveform.Also other waveforms (triangle, sawtooth can be used
Deng).For randomly or pseudo-randomly shaking, dither signal can be by low cutoff frequency (it can be DC) and higher cutoff frequency table
Sign.These cutoff frequencies can be is arranged when being electronically generated dither signal, or can be by Mechatronic Systems from
Right frequency response setting.Average frequency (or centre frequency) can be defined as the mean value of low cutoff frequency and higher cutoff frequency.
Average frequency in the range of 5Hz-1MHz is preferred.In frequency range set by cutoff frequency, jitter amplitude is not necessarily to
It is constant.
This jitter motion generates the equalization of the wavelength generated of laser 10 on small wavelength band.Choose jitter amplitude
The multiple adjacent laser cavity mold formulas reached will be in addition jumped by stochastic model with excitation.Therefore, the output mode of laser obtains
It is more stable to be equalized in these modes, and in time after equalization.By being equalized to each mode, to swash
A small amount of increased costs of the bandwidth of light device light generated obtain reproducible signal.
The amplitude of jitter motion determines mode included in laser output, and amplitude is bigger, included mode in output
Quantity it is bigger.Consider frequency band represented by neighboring modes band.Due to the band on edge in each shake not reproducibly
Excited target, therefore the residence time on any AD HOC in the central area of band is by the stop of the mode on the edge than band
Time is more reproducible.Correspondingly, there is compromise between the quantity of the mode in equalization and the reproducibility of laser output spectra.
Therefore, the quantity for equalizing the mode of appearance should come from the inside in band large enough to the most energy ensured in output light and
Mode on the edge of non-band.However, too wide mode band causes the frequency of the output spectra of light source to degrade.At of the invention one
In aspect, jitter amplitude is chosen, so that the quantity for the mode that equalization occurs is between 10 and 50.In one embodiment,
The quantity of mode is chosen for being greater than 20.However, the quantity for equalizing the mode of appearance is greater than 5 but small in some measurement situations
Embodiment in 10 is likely to be advantageous.
In one aspect of the invention, chattering frequency is chosen for being equal to the mechanical system including grating and associated section
The frequency of resonance.In this, it should be noted that by the arm that grating is connected to axis 23 be to be used to illustrate in Fig. 1.In many designs, do not deposit
In the physics arm for grating to be connected to " virtual " axis 23.Also the harmonic wave or subharmonic as the mechanical resonant be can use
This be arranged in the dither signal system critically important for the efficient coupling of mechanical system of frequency be advantageous.Chattering frequency
The preferably subharmonic of laser repetition rate.In one aspect of the invention, chattering frequency is the idol of laser repetition rate
Secondary subharmonic.
Randomized jitter signal or pseudo-random dither signal, which have, to be less likely to motivate the excellent of any resonance in measuring system
Point.In the case where randomized jitter signal, above-mentioned average frequency is the quantity of the change per second on amplitude direction.If utilized
Randomized jitter signal, then white noise sound source can be used for driving it relative to the equilbrium position of actuator 15.By with it is upper
It states the similar mode in cyclic drive source and the amplitude of noise source is set to provide the equalization of mode.
In another aspect of the invention, the frequency of the peak value of grating diffration function with it is desired using servo-system
Laser cavity modes alignment.Here, grating jitter amplitude very little compared with laser cavity FSR.In one embodiment, grating shakes width
Degree only covers small part laser cavity FSR.Percent 50 and preferably less than percent 15 of the small part less than laser cavity FSR
Embodiment be particularly useful.Detector 19 measures laser power, and servo-system adjustment actuator 15 will be measured
Power is maintained at maximum power, therefore maintains the peak value of optical grating diffraction function and the alignment of desired laser cavity modes.Again
The grating being properly aligned with is shown referring to Fig. 4, Fig. 4.If optical grating diffraction function slightly moves in frequency, laser power will
Decline.Therefore, if grating relative to current location shake, and equilbrium position by adjustment to maintain peak power output, then
Laser, which will remain in desired laser cavity modes, emits laser.
Referring now to Fig. 5.Only one of laser cavity modes 55 and 56 will emit laser at any given time.For this discussion
Purpose, it is assumed that the just transmitting laser of mode 55.Servo-system will attempt moving grating angle, so that power will be at maximum value.
Therefore, grating will be adjusted, so that diffraction curve peak value is moved to lower frequency.That is, grating will be positioned, so that
Diffraction curve has its maximum value now at mode 55.
As described above, in these embodiments, the necessary very little of jitter amplitude, to prevent shake generation mode from jumping.Also
It is to say, jitter amplitude should be less than the amplitude that the frequency shift (FS) of diffraction function maximum value will be made to reach more than free spectral range.One
In a exemplary embodiment, jitter amplitude is set, so that the change of the frequency of the peak value of diffraction curve is less than free spectral range
Half.
The selectivity of grating in the embodiment based on servo determines whether these embodiments can successfully be able to reality
It is existing.The deficiency if grating of the optical frequency of the mode near desired mode is decayed, even in adjustment diffraction curve
In the case where the feedback mechanism of the position of maximum value, mode, which jumps, to be occurred.As set forth above, it is possible to by increasing on grating
The size of beam diameter improve the selectivity of grating to which more grating groove light cover.It is straight in order to increase wave beam
Diameter, it is necessary to use biggish collimation lens；It is enough to ensure that however, lens must be moved to away from chip gain from chip gain
The distance of light filling lens.In prior art design, lens 22 are typically to be less than 3.2mm with the diameter less than 7mm
Focal length lenses.This arrangement generates the alignment laser with the diameter less than 7mm.In one aspect of the invention, thoroughly
Mirror 22 is the 6.5mm focal length lenses with the diameter of 15mm.In the case, if the flute density of grating be it is identical,
Grating wavelength selects bandwidth to reduce up to the factor greater than 2.
In the above-described embodiments, make for chip gain to be locked to the optical frequency selection element of one of its each mode
Use grating.However, it is also possible to optical element (such as one or more prisms) is selected using other optics in outside cavity gas laser,
To provide the selective attenuation for the light for leaving chip gain.
The above embodiment of the present invention is provided to show various aspects of the present invention.However, it should be understood that different specific real
Other embodiments of the present invention can be combined to provide by applying different aspect of the invention shown in example.In addition, according to the description of front
And attached drawing, various modifications of the invention will be apparent.Correspondingly, the present invention is only defined by the appended claims.
Claims (10)
1. a kind of outside cavity gas laser, comprising:
Chip gain；
Optical frequency selection element selectively will leave the gain as the function of the optical frequency in wavelength band
The light of chip decayed sends back to the chip gain, and the optical frequency selection element is by relative to leaving the increasing
The angle of the light of beneficial chip and distance characterization away from the chip gain, the angle and the distance be controlled by actuator, comes
Amplified from a part of light of the optical frequency selection element by the chip gain；And
Actuator drive trembles the angle in the movement by amplitude and average frequency characterization relative to balance angle
Dynamic, the amplitude is enough to motivate multiple adjacent laser cavity mold formulas of the chip gain.
2. outside cavity gas laser as described in claim 1, wherein the optical frequency selection element includes: grating, by wave
The optical diffraction that the chip gain is left in long band returns to the chip gain, and the grating is by relative to leaving the gain core
The angle of the light of piece and distance characterization away from the chip gain, the angle and the distance are controlled by the actuator, and one
Light after the diffraction of part is amplified by the chip gain.
3. outside cavity gas laser as described in claim 1, wherein the multiple adjacent laser cavity mold formula is greater than 5 and less than 50.
4. outside cavity gas laser as claimed in claim 2, wherein the actuator drive makes the angle by as including
The frequency of the resonance frequency of the mechanical system of the grating and shake.
5. outside cavity gas laser as claimed in claim 2, further includes: detector measures the light that the outside cavity gas laser generates
Power and servo described in actuator so that it is described by measurement power be maintained at maximum power, wherein the grating is by conduct
The diffraction curve characterization of the function of the frequency of the light amplified for the chip gain, wherein the laser cavity is by free light
Area's characterization is composed, and wherein, the angle is shaken so that the maximum value of the diffraction curve is reached by shake and is less than the laser
The amount of the free spectral range of chamber.
6. outside cavity gas laser as claimed in claim 2, wherein the chip gain presses first frequency chopping, and wherein,
The average frequency is less than the first frequency.
7. outside cavity gas laser as claimed in claim 6, wherein the average frequency is that the even Asia of the first frequency is humorous
Wave.
8. outside cavity gas laser as claimed in claim 2, further includes: collimation lens is hit in the light for leaving the chip gain
It hits before the grating according to the photogenerated collimated light beam, the collimated light beam has the diameter for being greater than 10mm and is greater than
The focal length of 4.4mm.
9. a kind of method for operating laser, the laser includes chip gain, grating and actuator, and the grating will
The optical diffraction that the chip gain is left in wavelength band returns to the chip gain, and the grating is by relative to leaving the gain
The angle of the light of chip and distance characterization away from the chip gain, the angle and the distance be controlled by the actuator,
The described method includes: the actuator is operated by actuator drive, so that the angle is by amplitude and average frequency
Relative to balance angle jitter in the movement of characterization.
10. method as claimed in claim 9, further includes: measure the power of laser light generated, and adjust institute
Actuator is stated, so that described be maintained at maximum power by measurement power, wherein the grating is by as the chip gain
The diffraction curve of the function of the frequency of the light amplified characterizes, wherein and the laser cavity is characterized by free spectral range, and its
In, the angle is shaken so that the maximum value of the diffraction curve is reached the free spectrum less than the laser cavity by shake
The amount in area.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US14/192,654 US9124068B1 (en) | 2014-02-27 | 2014-02-27 | Method and apparatus to reduce noise caused by mode hopping in external cavity lasers |
| US14/192,654 | 2014-02-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104882778A CN104882778A (en) | 2015-09-02 |
| CN104882778B true CN104882778B (en) | 2019-05-10 |
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| CN201510080016.2A Active CN104882778B (en) | 2014-02-27 | 2015-02-13 | The method and apparatus for jumping the noise of generation for reducing mode in outside cavity gas laser |
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| US (1) | US9124068B1 (en) |
| CN (1) | CN104882778B (en) |
| GB (1) | GB2523623B (en) |
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| US9124068B1 (en) * | 2014-02-27 | 2015-09-01 | Agilent Technologies, Inc. | Method and apparatus to reduce noise caused by mode hopping in external cavity lasers |
| US10732105B1 (en) * | 2019-02-15 | 2020-08-04 | Agilent Technologies, Inc. | Method and apparatus for characterizing laser gain chips |
| CN112582859A (en) * | 2020-12-14 | 2021-03-30 | 济南量子技术研究院 | Tunable terahertz wave generation device and method |
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Also Published As
| Publication number | Publication date |
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| GB201420089D0 (en) | 2014-12-24 |
| GB2523623A (en) | 2015-09-02 |
| US20150244150A1 (en) | 2015-08-27 |
| CN104882778A (en) | 2015-09-02 |
| GB2523623B (en) | 2016-04-20 |
| US9124068B1 (en) | 2015-09-01 |
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